This invention relates in general to manufacturing shingles, and in particular, to manufacturing laminated roofing shingles having underlays and overlays. More particularly, this invention pertains to a method of configuring a shingle manufacturing operation to enable the most efficient use of material and allow the manufacture of shingles of two different dimensions and shingle configurations using a common shingle mat size.
In the past, roofing shingles have had to satisfy two main functions when applied to a roof deck. The first function is to provide a durable, weatherproof covering for the roof deck. Roof shingles, whatever their form, are intended to provide a means of sheltering the structure below the shingles from precipitation and the deleterious effects of sun and wind. Roof shingles installed on the roof deck must perform these protecting functions for a reasonable period of time. The second function is to present an aesthetically pleasing architectural feature which enhances the overall appeal of the structure to which the shingles have been applied. This aesthetic function has been satisfied by providing asphalt shingles with various butt edge contours and surface treatments which operate to simulate more traditional, and in most cases more expensive, forms of roof coverings, such as, thatch, wooden shakes, slates, and even tiles of various forms.
Natural slate tiles have long been used as a roof covering. Natural slate is a durable material and is considered to provide an aesthetically pleasing look or appearance to a roof. A problem with natural slate roofs is that the installed cost is extremely high. Therefore, alternatives in the form of asphalt shingles that mimic the look of natural slate have been developed. In the case of asphalt shingles mimicking the look of natural slate, each shingle is typically provided with relatively wide tabs, such as for example, 9 inches wide, separated by relatively narrow cutouts, such as 1 inch wide. Ideally these slate-look shingles are made on a double wide shingle machine so that two shingles can be made simultaneously.
Another aesthetically pleasing shingle is a tab and cutout laminated shingle having a headlap portion and a tab portion including tabs and cutouts. Both the tabs and the cutouts are relatively wide, and the width of the tabs and the cutouts can vary. The area of the tabs is roughly equal to the area of the cutouts so that the two shingles can be simultaneously manufactured by cutting a common tab portion of a continuously moving granule covered sheet. The tabs and cutouts are complementary so that the cutouts and tabs of one side of the common tab portion match the tabs and cutouts, respectively, of the other side of the common tab portion. An example of this is shown in U.S. Pat. No. 5,102,487 to Lamb, which is hereby incorporated by reference in its entirety. Improvements in the design of these wide tab, wide cutout shingles include contrasting coloration between the tabbed overlay and the portions of the underlay that show through the cutouts, and the use of shadow lines to enhance the perception of depth or thickness of the shingle.
In order to produce shingles of both the slate-look type and the wide tab, wide cutout type at the same shingle manufacturing facility it is necessary to change the supply of shingle mat because invariably the width of the shingle mat needed for one type of shingle is different from the width of the shingle mat needed for another type of shingle. The necessity of changing the supply of shingle mat to switch from one type of shingle to the other increases the manufacturing cost for both types of shingles, both because of the expense and machine downtime during the changeover, and because of the need for greater storage of one or the other type of shingle. It would be advantageous if there could be developed a shingle manufacturing operation that better accommodated the need for making different types of shingle on a single shingle machine.
The above objects as well as other objects not specifically enumerated are achieved by a method of manufacturing laminated roofing shingles comprising coating a continuously supplied shingle mat having a width W with roofing asphalt to make an asphalt coated sheet, and subjecting the asphalt coated sheet to one of two subsequent processes. The first process comprises covering the asphalt coated sheet with granules in a first pattern suitable for making laminated shingles with an overlay having tabs and cutouts, where the area of the tabs approximately equals the area of the cutouts, thereby forming a first granule covered sheet. The first process also includes continuously dividing the first granule covered sheet into two continuous first overlay sheets and two continuous first underlay sheets, wherein the two first overlay sheets each have a headlap portion and the two first overlay sheets share a common tab portion having tabs and cutouts that are complementary so that the cutouts and tabs of one of the first overlay sheets are in registration with the tabs and cutouts, respectively, of the other one of the first overlay sheets, and wherein the sum of the height of each of the two continuous first underlay sheets plus the height of each of the headlap portions of the two first overlay sheets plus the height of the common tab portion substantially equals the width W of the shingle mat. The first process also includes laminating each one of the first underlay sheets beneath a respective one of the first overlay sheets to form laminated sheets, and cutting the laminated sheets into laminated shingles.
The second process comprises covering the asphalt coated sheet with granules in a second pattern suitable for making laminated shingles with an overlay having tabs and cutouts, where the area of the tabs is substantially greater than the area of the cutouts, thereby forming a second granule covered sheet. The second process also includes continuously dividing the second granule covered sheet into two continuous second underlay sheets and into two continuous second overlay sheets, wherein the two second overlay sheets each have a headlap portion and a tab portion, and wherein the sum of the height of each of the two continuous second underlay sheets plus the height of the headlap portion and tab portion of each of the two second overlay sheets substantially equals the width W of the shingle mat. The second process further includes laminating each one of the second underlay sheets beneath a respective one of the second overlay sheets to form laminated sheets, and cutting the laminated sheets into laminated shingles.
The invention includes switching from one of the first and second processes to the other process to make shingles according to either the first pattern or the second pattern using a common shingle mat having the width W.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.